Reduce size of scattergl

Author: mzaffalon

docs/src/building_traces_layouts.md

@@ -197,7 +197,7 @@ of the plot, whether the grid lines are drawn and the position of the legend.
     [layout reference documentation](https://plotly.com/julia/reference/layout/).
 
 
-## The `attr` function
+## [The `attr` function](@id attr)
 
 There is a special function named `attr` that allows you to apply the same
 keyword magic we saw in the trace and layout functions with underscores,

docs/src/examples/line_scatter2.md

@@ -368,7 +368,7 @@ One can use WebGL with [`scattergl`](https://plotly.com/julia/reference/scatterg
 ```@example
 using PlotlyJS
 
-N = 10000
+N = 3000
 plot(scattergl(x=randn(N), y=randn(N), mode="markers",
                marker=attr(color=randn(N), colorscale="Viridis", line_width=1)))
 ```

docs/src/extra-examples/line-and-scatter.md

@@ -131,7 +131,7 @@ ability to plot even more data!
 ```@example
 using PlotlyJS
 
-N = 100000
+N = 3000
 plot(scattergl(x=randn(N), y=randn(N), mode="markers",
                marker=attr(color=randn(N), colorscale="Viridis", line_width=1)))
 ```